NCM 112: Communicable Disease Overview

Medical Asepsis and Infection Types

• Medical asepsis involves practices aimed at confining specific microorganisms to a limited area to reduce their growth and transmission.
• Infection occurs when microorganisms invade body tissues, leading to their proliferation.
• Asymptomatic or subclinical infections do not show clinical symptoms but can still cause significant damage, such as cytomegalovirus (CMV) infections in pregnant women.

Pathogens and Disease Mechanisms

• Diseases can be communicable (transmitted person-to-person) or non-communicable (e.g., peritonitis).
• Pathogens can be classified as "true" pathogens, which can infect healthy individuals, or opportunistic pathogens that only affect those with weakened defenses.
• Pathogenicity refers to a microorganism's ability to produce disease, while virulence indicates the severity and damage caused during the infection process.

Airborne Transmission

• Airborne transmission involves pathogens suspended in the air, capable of infection when inhaled by susceptible individuals.
• Tuberculosis is an example of a disease spread through airborne transmission.
• Special air handling and isolation practices, such as Airborne Infection Isolation Rooms (AIIR), are necessary to prevent the spread of airborne diseases.

Defense Mechanisms Against Infection

• Strong host defenses can neutralize pathogens and prevent infection; these include:
  • Intact skin and mucous membranes.
  • Inflammatory responses and phagocytosis.
  • The immune system's active roles.
  • Physiological barriers like stomach acidity and urine flow.

Levels of Disease and Transmission Dynamics

• Epidemiological studies assess current disease incidence to determine infection levels in healthcare facilities.
• Definitions of disease occurrence:
  • Sporadic diseases occur infrequently.
  • Endemic diseases are consistently present in a region.
  • Epidemics refer to sudden increases in disease cases.
  • Pandemics indicate widespread epidemics across countries or continents.

Infection Types: Nosocomial vs. Community-Acquired

• Nosocomial infections, also known as hospital-acquired infections, arise during hospital stays and are not present at admission.
• Community-acquired infections exist at the time of admission without prior hospitalization history.
• Iatrogenic infections result from healthcare provider actions, often following medical or surgical interventions.

Infection Control and Prevention Strategies

• Effective infection control involves adhering to guidelines set forth by health authorities like the CDC.
• Key practices include:
  • Hand hygiene immediately after patient contact.
  • Wearing personal protective equipment (PPE), such as masks and eye protection, to safeguard against infection.
  • Decoding transmission routes: airborne, droplet, and contact transmission.

Types of Immunity and Vaccination

• Active immunity is achieved via vaccination or exposure to pathogens, while subclinical immunity results from constant exposure to specific diseases.
• Types of antigens include:
  • Inactivated (killed) organisms that require multiple doses for lasting immunity.
  • Attenuated (live) organisms, which typically require a single dose for long-term immunity.